JavaScript and PHP Validation and Error Handling CHAPTER 17

Validating User Input with JavaScript  JavaScript validation should be considered an assistance more to your users than to your websites  hackers can quite easily simulate your web forms and submit any data of their choosing  some users disable JavaScript

The validate.html Document (Part One)  inputs being requested will be forename, surname, username, password, age, and address  Example A form with JavaScript validation  this form will display correctly but will not self-validate, because the main validation functions have not yet been added

The validate.html Document (Part Two)  a set of six functions that do the actual form field validation  Example Part two of the JavaScript validation form

Regular Expressions  regular expressions, which are supported by both JavaScript and PHP  Matching Through Metacharacters  Every regular expression must be enclosed in slashes. Within these slashes, certain characters have special meanings; they are called metacharacters

Fuzzy Character Matching  The dot (.) is particularly useful  A simple way to do so is: / /

Grouping Through Parentheses  Character Classes  Indicating a Range  Negation  Some More Complicated Examples

Summary of Metacharacters  Table Regular expression metacharacters  Table Some example regular expressions  General Modifiers  Using Regular Expressions in JavaScript  Using Regular Expressions in PHP

Redisplaying a Form After PHP Validation  Example The adduser.php program